DEFCON

The Saturday of DEFCON provided a fast and furious couple of hours of everything Android. In the past, talks had typically focused on Android’s sandbox and NFC elements. This year, three talks took a look at some slightly different vectors that developers, pen-testers and even general users should be aware of.

The first Android talk was courtesy of Craig Young from TripWire. He presented his research on what happens when an application requests access to part of the user’s Google account. Through some great live demos, Craig showed that, if a user grants access to, for example, their Google Finance data, the same application can make a request for a second token and send it off to a server. This token doesn’t just give access to the Finances, but all of the user’s Google account, including Google drive, Google Code repositories and even their search history. Thankfully, Google have been working diligently to lock down the range of access available via this attack; changing passwords now requires the re-entry of the current password.

A very interesting point was that the demo app that performed the multiple token requests was placed on the Google Play store (for a fee of over $100 to keep out would-be downloaders). His conclusions were that the app remained on the store for a number of weeks in spite of a very obvious method in the code and even an overt (and slightly barbed) application description. It is interesting to see that Bouncer, for one reason or another, failed to detect and remove such an application.

“Looks like I picked the wrong day to stop sniffing packets!”

Second up came Jamie Sanchez with a look at implementing an Intrusion Detection System, on Android. His goal was to detect and defend against scans and exploits from a number of different protocols in real time, keeping the user safe as they browsed. He accomplished this through modification of the IP tables using the QUEUE command to build a stack of packets to check (loved the “looks like I picked the wrong day to stop sniffing packets” slide!). His proof of concepts showed protection against nmap scans (returning spoofed results), and even protection against webkit exploits. Very impressive.

Finally, Pau Oliva Fora of ViaForensics introduced his latest area of research – Assessing implementations of the Security Enhanced Android. He showed that, although SE Android is a good idea, many vendors are yet to implement it in such a way that its Mandatory Access Controls (MAC) are an effective deterrent to a skilled attacker. One such implementation relied on a system application enabling the MAC once the device had finished booting. Unfortunately, in the time between booting began and the application enforcing MAC, Pau managed to gain access to the package manager and disable the SE Android application. It just goes to show that a great idea is nothing without great implementation!

It’s fantastic to see so many new avenues of research in Android to keep us all on our toes. A massive thanks to the three speakers and everyone that helped them in producing three of my favourite talks at DEFCON this year. Thought-provoking, relevant and well-delivered. Thanks guys!

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